The Thunder reeled in the Heat's 9-150 with seven balls to spare at North Sydney Oval, thanks predominantly to an unbroken 97-run stand between Litchfield (52 not out), a year-10 student from Orange, and Alex Blackwell (42 not out), a former Test veteran.
Openers Rachel Priest (31 off 17 balls) and Naomi Stalenberg (18 off 11) went hard early but the chase began to stall when Litchfield, who joined Blackwell in the middle was restricted to 11 off her first 22 deliveries.
But Litchfield, with some reassuring guidance from Blackwell - who again batted superbly - stayed calm and eventually started hitting the ball as cleanly as the video of her that went viral on social media recently.
"I can't believe I did that ... it's crazy," said elated Litchfield, player-of-the-match in just her second game.
"I should have been out first or second ball but I'm glad we got there in the end.
"To have Alex out there again was awesome.
"I was about to get very angry and she kept me very level-headed."
When Litchfield thumped three boundaries off one Sammy-Jo Johnson over, the Heat cracked.
The visitors started the match spritely when Beth Mooney smoked 35 of the first 44 runs scored.
Jess Jonassen chimed in with 42 but the defending champions lost wickets too regularly to set a bigger target.
Spinners Samantha Bates (3-33) and Pakistani Nida Dar (2-22) bowled superbly for the Thunder before Litchfield stole the show.